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Fylane
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Free tools · PDF

Protect PDF

A password to open, optionally another to edit. Modern encryption only.

Free · no sign-up · no watermark · up to 50 MB · uploads deleted after 24 hours, results after 7 days.

How to protect pdf

  1. Drop the PDF.
  2. Type the password to open it.
  3. Press Protect and download.

What happens to your file

The file is encrypted with AES-256 — the only cipher this tool writes. Older RC4 encryption, which some tools still offer, is not offered because it can be stripped in seconds.

Contents are unchanged; anyone with the password sees exactly the document you had.

Questions

Will it open in every reader?

AES-256 has been supported by Acrobat since version 9, by Preview, Chrome, Firefox and Edge. Readers from before 2008 may not open it.

Is the password stored?

No. It is used to encrypt this one file and discarded with the job.

Do this in code

curl -X POST https://api.fylane.dev/v1/jobs \
  -H "Authorization: Bearer $FYLANE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "file_id": "<file id>",
    "operation": "pdf.encrypt",
    "options": {
      "password": "<password>",
      "owner_password": "<password>"
    }
  }'

The same operation, pdf.encrypt — AES-256 password protection; the only strength offered. Upload first with the quickstart; every option is on the operations page. 500 free credits a month, then $5 per thousand.